21153003500 has 48 divisors (see below), whose sum is σ = 46430529600. Its totient is φ = 8418643200.

The previous prime is 21153003499. The next prime is 21153003503. The reversal of 21153003500 is 530035112.

It is a Harshad number since it is a multiple of its sum of digits (20).

It is not an unprimeable number, because it can be changed into a prime (21153003503) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 6797 + ... + 205796.

It is an arithmetic number, because the mean of its divisors is an integer number (967302700).

Almost surely, 2^21153003500 is an apocalyptic number.

21153003500 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21153003500, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (23215264800).

21153003500 is an abundant number, since it is smaller than the sum of its proper divisors (25277526100).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

21153003500 is a wasteful number, since it uses less digits than its factorization.

21153003500 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 212811 (or 212799 counting only the distinct ones).

The product of its (nonzero) digits is 450, while the sum is 20.

Adding to 21153003500 its reverse (530035112), we get a palindrome (21683038612).

The spelling of 21153003500 in words is "twenty-one billion, one hundred fifty-three million, three thousand, five hundred".